Buffalo QB Leinart has much on the line in Bills preseason finale against Lions

Thanks to injuries to the Bills' top two quarterbacks, the 2004 Heisman Trophy winner has an opportunity to continue his career by competing for a backup spot in Buffalo. Signed Sunday, Leinart gets a one-game tryout to prove himself Thursday, when Buffalo (2-1) closes the preseason hosting Detroit (2-1).

Leinart said he's humbled and excited to get a shot after spending the offseason out of football.

This is not what the former Southern California star anticipated in 2006, when he was drafted 10th overall by the Arizona Cardinals. He spent four unproductive seasons in Arizona before losing the starting job to Kurt Warner.

After stints in Houston and Oakland, he's on his third team in as many years.